Audi D2 A8/A8L/S8 (1997-2003) FAQ Digest
11-22-2008, 01:07 PM
#91
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Modification Version 1
5HP24A Transmission, Valve Body Fix - Modification Version 1
This is version 1 fix because different modifications may come as needed.
I originally purposed that the transmission thump issue was due to wear and subsequent loss of pressure to the torque converter clutch (tcc). I also believed that making changes to (mainly) one orifice in the leg that controls the tcc would solve the issue. Since inspecting the open transmission, I have an even easier way to increase pressure in this leg!
DISCLAIMER, PLEASE READ:
I am sorry to post this so incredibly late. I know that we have real issues with our transmissions and instead of addressing the problem, I garaged the Audi and just bought a new vehicle. In my defense though, I really needed a truck; hauling a trailer with the Audi just seemed to be an injustice.
I have yet to prove this fix or to put the Audi back together. I am posting this now because it may be a while before I can get to it.
This is the crux of it. Each of the 5 pressure regulators (or EDS variable controls) has an adjustable pressure set screw in the back! How convenient. I still don't recommend adjusting the main pressure regulator because of possible damage to the valve body but the torque converter clutch leg should be fine.
<img src="http://pictureposter.audiworld.com/125817/regulator1.jpg">
A really good tutorial for getting to the valve body can be found on Paul's AudiPages.com site so I am not going to reproduce it here.
<a href="http://www.audipages.com/Tech_Articles/auto_transmission/autotranservicing.html">Transmission fluid and filter replacement procedure at AudiPages.com</a>
The hex key (Allen) in the picture is 2 mm (metric). You will probably strip this little screw if you use a standard size hex key. The set screw seems to be glued in place and you need to break it free to reset the position. I removed the regulator and gently turned the screw cw and ccw until it moved freely. If you are really good (lucky), you may be able to do this modification without removing the regulator. But I recommend changing all the O rings and cleaning the screens anyway. You have 4 tries to do this correctly since 4 regulators are the same. If you strip or crack one, before it breaks free, it is still good, just not adjustable.
<img src="http://pictureposter.audiworld.com/125817/regulator2.jpg">
<img src="http://pictureposter.audiworld.com/125817/VB_controls.jpg">
The previous picture is viewing the valve body of the open transmission from rear to front. I have removed the first 3 regulators. The regulators and solenoids from left to right are:
EDS1 - main pressure regulator - replace 13mm x 2mm O ring (Note that all O rings are Viton 70 or 75 grade)
EDS4 - regulates the torque converter clutch (the one we adjust) - replace 13.5mm x 2mm O ring
EDS3 - same part as EDS4 - replace O ring
EDS2 - same part as EDS4 - replace O ring
EDS5 - same part as EDS4 - replace O ring
MV1 - magnetic valve solenoid - no O ring
MV2 - no O ring
MV3 - no O ring
The electrical connectors should come off easily. Note the catch at the top of the connector that can be teased if you have troubles. Remove 9 T27 torx bolts and the clip rail to get the regulators out. For reinstallation, note that the 'fingers' on this rail holding the regulators are slightly bent toward the valve body.
<img src="http://pictureposter.audiworld.com/125817/reg-sol_clip.jpg">
A standard (flat) screwdriver works well to pop out the regulators. Don't forget to clean the screens.
I will install the EDS4 with a 3/4 clockwise turn to increase the pressure. It may be not enough or too much. Please don't wait for me though. I may not get to this for a while. If others try this, please let me know of your findings and I will edit them in here.
This is version 1 fix because different modifications may come as needed.
I originally purposed that the transmission thump issue was due to wear and subsequent loss of pressure to the torque converter clutch (tcc). I also believed that making changes to (mainly) one orifice in the leg that controls the tcc would solve the issue. Since inspecting the open transmission, I have an even easier way to increase pressure in this leg!
DISCLAIMER, PLEASE READ:
I am sorry to post this so incredibly late. I know that we have real issues with our transmissions and instead of addressing the problem, I garaged the Audi and just bought a new vehicle. In my defense though, I really needed a truck; hauling a trailer with the Audi just seemed to be an injustice.
I have yet to prove this fix or to put the Audi back together. I am posting this now because it may be a while before I can get to it.
This is the crux of it. Each of the 5 pressure regulators (or EDS variable controls) has an adjustable pressure set screw in the back! How convenient. I still don't recommend adjusting the main pressure regulator because of possible damage to the valve body but the torque converter clutch leg should be fine.
<img src="http://pictureposter.audiworld.com/125817/regulator1.jpg">
A really good tutorial for getting to the valve body can be found on Paul's AudiPages.com site so I am not going to reproduce it here.
<a href="http://www.audipages.com/Tech_Articles/auto_transmission/autotranservicing.html">Transmission fluid and filter replacement procedure at AudiPages.com</a>
The hex key (Allen) in the picture is 2 mm (metric). You will probably strip this little screw if you use a standard size hex key. The set screw seems to be glued in place and you need to break it free to reset the position. I removed the regulator and gently turned the screw cw and ccw until it moved freely. If you are really good (lucky), you may be able to do this modification without removing the regulator. But I recommend changing all the O rings and cleaning the screens anyway. You have 4 tries to do this correctly since 4 regulators are the same. If you strip or crack one, before it breaks free, it is still good, just not adjustable.
<img src="http://pictureposter.audiworld.com/125817/regulator2.jpg">
<img src="http://pictureposter.audiworld.com/125817/VB_controls.jpg">
The previous picture is viewing the valve body of the open transmission from rear to front. I have removed the first 3 regulators. The regulators and solenoids from left to right are:
EDS1 - main pressure regulator - replace 13mm x 2mm O ring (Note that all O rings are Viton 70 or 75 grade)
EDS4 - regulates the torque converter clutch (the one we adjust) - replace 13.5mm x 2mm O ring
EDS3 - same part as EDS4 - replace O ring
EDS2 - same part as EDS4 - replace O ring
EDS5 - same part as EDS4 - replace O ring
MV1 - magnetic valve solenoid - no O ring
MV2 - no O ring
MV3 - no O ring
The electrical connectors should come off easily. Note the catch at the top of the connector that can be teased if you have troubles. Remove 9 T27 torx bolts and the clip rail to get the regulators out. For reinstallation, note that the 'fingers' on this rail holding the regulators are slightly bent toward the valve body.
<img src="http://pictureposter.audiworld.com/125817/reg-sol_clip.jpg">
A standard (flat) screwdriver works well to pop out the regulators. Don't forget to clean the screens.
I will install the EDS4 with a 3/4 clockwise turn to increase the pressure. It may be not enough or too much. Please don't wait for me though. I may not get to this for a while. If others try this, please let me know of your findings and I will edit them in here.
12-02-2008, 10:54 AM
#92
AudiWorld Super User
Thread Starter
Troubleshooting the Cruise Control System
<ul><li><a href="https://forums.audiworld.com/a4/msgs/2601924.phtml">https://forums.audiworld.com/a4/msgs/2601924.phtml</a</li></ul>
12-06-2008, 03:39 AM
#94
AudiWorld Super User
upper oil pan gasket
<center><img src="http://pictureposter.audiworld.com/55607/upperpangasket3.jpg"></center><p>If you are certain that the "upper" oil pan gasket is leaking it can be replaced.
Replacing it costs very little but is a LOT of work. The good news is that it's also pretty simple.
The first and biggest part of the job is removing the subframe. See Transmission removal procedure on audipages.com.
Once the subframe is out of the way, remove the lower oil pan which is just a series of 10mm bolts around the outside (32v). The 40v substitutes triple square torx.
At this point, you can start removing fasteners that attach the upper pan to the engine block. There are a whole bunch and some of them will be "inside" the upper pan. You won't see these until the lower pan is removed.
There also a couple that are recessed in the two holes in the transmission bell housing. Look straight up and you should see them. Finally, there are one or two bolts that run horizontal which are standard hex bolts.
Note: some of the triple square bolts hold the oil pan baffle in place. It's just a plastic baffle nothing to worry about. Make note of the position so you can re-install.
The 40v engine uses RTV (the dealer stuff is white and very good) for both the upper and lower pans.
The 32v uses conventional gaskets instead.
Replacing it costs very little but is a LOT of work. The good news is that it's also pretty simple.
The first and biggest part of the job is removing the subframe. See Transmission removal procedure on audipages.com.
Once the subframe is out of the way, remove the lower oil pan which is just a series of 10mm bolts around the outside (32v). The 40v substitutes triple square torx.
At this point, you can start removing fasteners that attach the upper pan to the engine block. There are a whole bunch and some of them will be "inside" the upper pan. You won't see these until the lower pan is removed.
There also a couple that are recessed in the two holes in the transmission bell housing. Look straight up and you should see them. Finally, there are one or two bolts that run horizontal which are standard hex bolts.
Note: some of the triple square bolts hold the oil pan baffle in place. It's just a plastic baffle nothing to worry about. Make note of the position so you can re-install.
The 40v engine uses RTV (the dealer stuff is white and very good) for both the upper and lower pans.
The 32v uses conventional gaskets instead.
12-06-2008, 03:46 AM
#95
AudiWorld Super User
transmission removed - other things to consider changing
<ul><li><a href="https://forums.audiworld.com/a8/msgs/177184.phtml">transmission removed? check this list</a></li></ul>
12-24-2008, 04:01 AM
#97
AudiWorld Super User
please delete this post for now, Bosch pump only works for one side of tank. The correct VDO part #
is 405-052-002-001Z.
A couple of people are trying to source it, stay tuned.
A couple of people are trying to source it, stay tuned.
01-12-2009, 11:34 AM
#100
AudiWorld Super User
Thread Starter
Another Fix for the Intake Manifold - freeing up stuck intake manifold actuators
<ul><li><a href="https://forums.audiworld.com/a8/msgs/179821.phtml">https://forums.audiworld.com/a8/msgs/179821.phtml</a</li></ul>